1. Field of the Invention
The present invention relates to a frequency synthesizer module for digital terrestrial broadcasting, and more particularly, to a synthesizer module which can easily set an adequate oscillation frequency according to an area with common specifications, regardless of a destination area.
2. Description of the Related Art
[Description of Prior Art]
A conventional synthesizer module for digital terrestrial broadcasting separates every channel range into several bands, selects a channel number in a band with a digital switch, and sets an oscillation frequency (see Non-patent Document 1).
However, while the above frequency setting approach can cope with the setting only for a limited destination area where channel frequencies are arranged at fixed frequency intervals as in Japan, a synthesizer module for common worldwide use is demanded to have specifications that can permit frequency setting in 1-Hz step.
A synthesizer module compatible with all bands in 1-Hz step has been developed and provided (see Non-patent Document 2).
The prior arts that disclose the setting of the channel of a frequency synthesizer include those in Japanese Laid-Open Patent Application publication H10 (1998)-322252 (Patent Document 1), Japanese Laid-Open Patent Application publication H05 (1993)-041664 (Patent Document 2), Japanese Laid-Open Patent Application publication H08 (1996)-340254 (Patent Document 3), and Japanese Laid-Open Patent Application publication 2000-307458 (Patent Document 4).
Patent Document 1 describes such a configuration of a frequency synthesizer that a parameter or so on corresponding to a group setting mode is read from a memory, and an arbitrary frequency can be set by means of a switch or the like.
Patent Document 2 describes such a configuration of a frequency synthesizer that a predetermined frequency can be set using a program divider.
Further, patent Document 3 describes a frequency synthesizer having such a configuration that a frequency setting parameter is read from a memory, and an arbitrary frequency which is equal to or less than a half of an input lock frequency can be set.
Patent Document 4 describes such a configuration of a PLL incorporated tuner that a band and the center frequency of an intermediate frequency can be arbitrarily set by data control.
Patent Document 1: Japanese Laid-open Patent Application Publication H10(1998)-322252
Patent Document 2: Japanese Laid-open Patent Application Publication H05(1993)-041664
Patent Document 3: Japanese Laid-open Patent Application Publication H08(1996)-340254
Patent Document 4: Japanese Laid-open Patent Application Publication 2000-307458
Non-patent Document 1: SYSTEC RESEARCH Inc., “UHF Band Frequency Synthesizer for SFN & MFN of Digital TV Broadcasting Model: DCN-SP501/801-Bxx” November 2005 http://www.systec-r.com/pdf/dcn-sp501j.pdf
Non-patent Document 2: SYSTEC RESEARCH Inc., “UHF Band Frequency Synthesizer Model: DTV-2000N” September 2005 http://www.systec-r.com/pdf/dtv2000nj.pdf
While there are the above-described two conventional setting approaches, however, a problem arises such that simple integration of both approaches alone cannot easily set an oscillation frequency in view of the convenience of a frequency setting person.